Method for driving touch panel

ABSTRACT

A method for driving a touch panel including driving lines, sensing lines, and node capacitors between neighboring and/or overlapping driving lines and sensing lines is disclosed. The method includes selecting two or more of the driving lines, and simultaneously driving the selected driving lines with driving signals. Each driving signal has three or more voltages of different levels.

This application claims the benefit of the Korean Patent Application No.10-2013-0022088, filed on Feb. 28, 2013, which is hereby incorporated byreference as if fully set forth herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

Embodiments of the present disclosure relate to a method for driving atouch panel.

2. Discussion of the Related Art

Generally, measurement of the capacitance of each sensing node in atouch panel is achieved by applying a pulse sequence at a specificfrequency through a driving line by a driving unit, and measuring asignal received through a sensing line by a sensing unit.

In this case, the frequency of the pulse sequence may be influenced byvarious environmental noise such as charger noise and fluorescent lampnoise. To this end, methods for suppressing influence of suchenvironmental noise may be applied. In addition, an appropriate signalprocessing scheme may be applied to the sensing unit in order to extracta signal component corresponding to the measured capacitance.

SUMMARY OF THE INVENTION

Embodiments of the present disclosure provide a method for driving atouch panel capable of reducing a harmonic component included in adriving signal, and achieving an enhancement in sensitivity and jitterimmunity.

Additional advantages, objects, and features of the embodiments will beset forth in part in the description which follows and in part willbecome apparent to those skilled in the art upon examination of thefollowing or may be learned from practice of the embodiments. Theobjectives and other advantages of the embodiments may be realized andattained by the structure particularly pointed out in the writtendescription and claims hereof as well as the appended drawings.

To achieve these objects and other advantages and in accordance with thepurpose of the embodiments, as embodied and broadly described herein, amethod for driving a touch panel including driving lines, sensing lines,and node capacitors formed between neighboring or overlapping ones ofthe driving lines and the sensing lines includes selecting two or moreof the driving lines, and simultaneously driving the selected drivinglines by driving signals, wherein each of the driving signals has threeor more voltages of different levels.

Each driving signal may be a periodic signal, and may have three or morevoltages of different levels in every period thereof.

Each driving signal may include a first signal portion or time periodhaving a first voltage level, a second signal portion or time periodhaving a second voltage level, and a third signal portion or time periodhaving a third voltage level. The first voltage level, the secondvoltage level, and the third voltage level may be different.

The first voltage level may be higher than the second voltage level. Thesecond voltage level may be higher than the third voltage level.

The first voltage level may be a positive (+) voltage. The secondvoltage level may be 0 or a ground potential, and the third voltagelevel may be a negative (−) voltage.

The first signal portion or time period and the third signal portion ortime period may alternate. The second signal portion or time period maybe between the first signal portion or time period and the third signalportion or time period.

Each driving signal may have a duty ratio second within a range of morethan 0.25, but less than 1. The duty ratio of each driving signal may bea ratio or percentage of a sum of a length of the first signal portionor time period and a length of the third signal portion or time periodin each period of the driving signal.

The different portions of the driving signal may have the same phase.

The driving signal applied to at least one of the selected driving linesmay have a phase different from other driving signals applied to other(e.g., the remaining) driving lines.

The first signal portion or time period and the third signal portion ortime period of each driving signal may have equal lengths within oneperiod of the driving signal.

The second signal portion or time period may be before the first signalportion or time period and/or after the third signal portion or timeperiod.

In another aspect, a method for driving a touch panel including drivinglines, sensing lines, and node capacitors between overlapping ones ofthe driving lines and the sensing lines includes selecting two or moreof the driving lines, and simultaneously driving the selected drivinglines by driving signals, wherein each driving signal is a periodicsignal and has a period comprising a first portion or time period inwhich the driving signal has a first voltage level, a second portion ortime period in which the driving signal has a second voltage level lowerthan the first voltage level, and a third portion or time period inwhich the driving signal has a third voltage level lower than the secondvoltage level.

Each driving signal may have a duty ratio within a range of more than0.25, but less than 1. The duty ratio of each driving signal may be aratio or percentage of a sum of a length of the first portion or timeperiod and a length of the third portion or time period in each periodof the driving signal.

The second portion or time period of the driving signal may be presentbetween the first portion or time period and the third portion or timeperiod.

The first portion or time period and the third portion or time periodmay be equal.

The length of the second portion or time period may be shorter than thefirst portion or time period and/or the third portion or time period.

The different portions or time periods of an individual driving signalmay have the same phase.

The driving signal applied to at least one of the selected driving linesmay have a phase different from other driving signals applied to other(e.g., the remaining) driving lines.

In another aspect, a method for driving a touch panel including drivinglines, sensing lines, and node capacitors between overlapping ones ofthe driving lines and the sensing lines includes selecting two or moreof the driving lines, simultaneously driving the selected driving linesby driving signals having two or more voltages of different levels, andreceiving an overlapped or combined signal from thesimultaneously-driven driving signals, wherein the overlapped orcombined signal is a periodic signal having three or more voltages ofdifferent levels.

The overlapped or combined signal may have a period comprising, insequence, a first portion or time period in which the overlapped orcombined signal has a first voltage level, a second portion or timeperiod in which the overlapped or combined signal has a second voltagelevel lower than the first voltage level, a third portion or time periodin which the overlapped or combined signal has a third voltage levellower than the second voltage level, and a fourth portion or time periodin which the overlapped or combined signal has the second voltage level.

Embodiments of the present disclosure may reduce a harmonic componentincluded in a driving signal while achieving an enhancement insensitivity and jitter immunity.

It is to be understood that both the foregoing general description andthe following detailed description of the embodiments are exemplary andexplanatory and are intended to provide further explanation of theembodiments as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

Arrangements and embodiments may be described in detail with referenceto the following drawings. In the drawings:

FIG. 1 is a diagram illustrating an exemplary configuration of atouchscreen device according to one or more embodiments of the presentdisclosure;

FIG. 2 is a waveform diagram illustrating an example of a driving signalapplied to two or more driving lines illustrated in FIG. 1;

FIG. 3 is a circuit diagram illustrating an embodiment of a sensingcircuit included in the sensing unit illustrated in FIG. 1;

FIG. 4 is a waveform and/or diagram illustrating examples of a drivingsignal having two voltages of different levels and a driving signalhaving three voltages of different levels in accordance with one or moreembodiments of the present disclosure;

FIG. 5 is a waveform illustrating results of a simulation showing aharmonic component of the driving signal illustrated in FIG. 4 as havingtwo voltages of different levels;

FIG. 6 is a waveform illustrating results of a simulation showing aharmonic component of the driving signal according to the embodiment(s)of FIG. 4;

FIG. 7 is a waveform diagram illustrating a signal received by thesensing unit from each sensing line when driving signals having the samephase are simultaneously applied to two or more driving linescorresponding to the sensing line, respectively;

FIG. 8 is a waveform diagram illustrating an example in which at leastone driving signal simultaneously applied to driving lines has a phasedifferent from those of the remaining driving signals;

FIG. 9 is a method for simultaneously driving two driving lines inaccordance with one or more embodiments of the present disclosure;

FIGS. 10A to 10C are waveform diagrams illustrating examples of twoexemplary driving signals illustrated in FIG. 9; and

FIG. 11 is a waveform diagram illustrating a method for simultaneouslydriving two driving lines in accordance with one or more additionalembodiments.

DETAILED DESCRIPTION OF THE INVENTION

In the following description of various embodiments, it will beunderstood that, when an element such as a layer (film), region,pattern, or structure is referred to as being “on” or “under” anotherelement, it can be directly on or under the other element, or it can beindirectly on or under the other element with one or more interveningelements present. In addition, terms such as “on” or “under” should beunderstood on the basis of the drawings.

In the drawings, dimensions of layers may be exaggerated, omitted orschematically illustrated for clarity and convenience of description. Inaddition, dimensions of constituent elements do not entirely ornecessarily reflect actual dimensions thereof. The same referencenumerals denote the same constituent elements, respectively.Hereinafter, a method for driving lines of a touch panel in accordancewith one or more embodiments and a touchscreen device according to oneor more embodiments will be described with reference to the accompanyingdrawings.

FIG. 1 is a diagram illustrating a configuration of a touchscreen device100 according to one or more embodiments of the present disclosure.

Referring to FIG. 1, the touchscreen device 100 includes a touch panel10, a driving unit 20, a sensing unit 30, and a control unit 40.

The touch panel 10 provides a plurality of sensing nodes P11 to Pnm (nand m being natural numbers greater than 1) having substantiallyindependent functions, but different positions.

The sensing nodes P11 to Pnm may be described as coordinates, sensingpoints, nodes, or a sensing node array.

For example, the touch panel 10 may include a plurality of driving linesX1 to Xn (n being a natural number greater than 1), a plurality ofsensing lines Y1 to Ym (m being a natural number greater than 1), andnode capacitors C11 to Cnm (n and m being natural numbers greaterthan 1) formed between overlapping driving lines X1 to Xn and sensinglines Y1 to Ym.

The driving lines X1 to Xn may be described as driving signal lines ordriving electrodes.

The sensing lines Y1 to Ym may be described as sensing signal lines orsensing electrodes.

Although the driving lines and sensing lines are illustrated in FIG. 1as intersecting each other, embodiments of the present disclosure arenot limited to such an arrangement. The driving lines and sensing linesmay be embodied such that they do not intersect each other.

Each sensing node (for example, the sensing node P11) may be defined bythe first node capacitor (for example, C11) between the first drivingline (for example, X1) and the first sensing line (for example, Y1).

For example, each driving line Xi (i being a natural number satisfying0<i≦n) and each sensing line Yj (j being a natural number satisfying0<j≦m) may be isolated from each other through insulation, and one nodecapacitor Cij may be formed between the driving line Xi and the sensingline Yj.

For example, the touch panel 10 may include an electrode pattern layer(not shown) including sensing electrodes and driving electrodes spacedapart from each other, a substrate (not shown) at a front side of theelectrode pattern layer, and an insulating layer (not shown) at a backside of the electrode pattern layer. The electrode pattern layer mayhave various layouts in accordance with a designing method appliedthereto.

The electrode pattern layer may include least one transparent conductivematerial, for example, indium tin oxide (ITO), tin oxide (TO), indiumzinc oxide (IZO), indium tin zinc oxide (ITZO), indium aluminum zincoxide (IAZO), indium gallium zinc oxide (IGZO), indium gallium tin oxide(IGTO), aluminum zinc oxide (AZO), antimony tin oxide (ATO), galliumzinc oxide (GZO), carbon nanotubes, a conductive polymer, silver, andtransparent copper ink.

The electrode pattern layer may be on or over one or more layers ofglass or plastic, to form a sensing node array including sensing nodesP11 to Pnm (n and m being natural numbers greater than 1).

The substrate may comprise or have the form of a dielectric filmexhibiting high light transmissivity. For example, the substrate mayinclude at least one of glass, polyethylene terephthalate (PET),polyethylene naphthalate (PEN), a polyimide (PI), or a (meth)acrylatepolymer.

The insulating layer may be a transparent insulating layer including,for example, PET. In another embodiment, a shield layer (not shown) maybe beneath the insulating layer in order to eliminate electromagneticinterference (EMI) and noise entering the electrode pattern layer.

The touch panel 10 may be merged with a layer for display or may share adriving or sensing path with the layer in accordance with an appropriatepanel designing method.

When the touch panel 10 is not coupled with a display, a two-dimensionalsensing node array may be configured in accordance with an appropriatemethod. Embodiments are also applicable to a touch sensing systemcomprising or constituted by a two-dimensional sensing node array.

The driving unit 20 is electrically connected with a plurality ofdriving lines X1 to Xn (n being a natural number greater than 1), tosupply a driving signal to one or more of the driving lines X1 to Xn.

For example, the driving unit 20 may simultaneously supply a drivingsignal to two or more of the driving lines X1 to Xn.

Here, “simultaneously” may include not only events occurring nearlysimultaneously, but also events occurring precisely simultaneously. Forexample, events occurring simultaneously may mean events that nearlysimultaneously start, and nearly simultaneously end, and/or eventshaving periods that at least partially overlap.

The driving signal applied to two or more driving lines may have threeor more voltages of different levels, and may be a periodic signal.

For example, the driving signal applied to two or more driving lines mayhave three voltages of different levels within each period.

FIG. 2 illustrates an example of a driving signal Vd applied to two ormore of the driving lines illustrated in FIG. 1.

Referring to FIG. 2, the driving signal Vd may have a first voltagelevel, +Vp, a second voltage level, Vss, and a third voltage level, −Vn.The first voltage level V+p, second voltage level Vss, and third voltagelevel −Vn may have different values, respectively.

For example, the driving signal Vd may include a first signal portion ortime period V1 having a first voltage level +Vp, a second signal portionor time period V2 having a second voltage level Vss, and a third signalportion or time period V3 having a third voltage level −Vn. In thiscase, the first voltage level V+p, second voltage level Vss, and thirdvoltage level −Vn may have different values, respectively.

The first voltage level +Vp may be higher than the second voltage levelVss, and the second voltage level Vss may be higher than the thirdvoltage level −Vn (+Vp>Vss>−Vn).

For example, the first voltage level +Vp may be a positive (+) voltage.The second voltage level Vss may be 0 or a ground potential. The thirdvoltage level −Vn may be a negative (−) voltage.

The first signal portion or time period V1 and third signal portion ortime period V3 may alternate. The second signal portion or time periodV2 may be between the first signal portion or time period V1 and thethird signal portion or time period V3. Alternatively, the second signalportion or time period V2 may be before the first signal portion or timeperiod V1 and/or after the third signal portion or time period V3.

In each period T of the driving signal Vd, the first signal portion,value and/or time period V1, the second signal portion, value and/ortime period V2, and the third signal portion, value and/or time periodV3 may be referred to as a “first portion or time period Ta1”, a “secondportion or time period Ta2”, and a “third portion or time period Ta3”,respectively.

Thus, each period T of the driving signal Vd may include the firstportion or time period Ta1, second portion or time period Ta2, and thirdportion or time period Ta3. In each period T, the second portion or timeperiod Ta2 may be present between the first period Ta1 and the thirdperiod Ta3.

The second portion or time period Ta2 present between the first portionor time period Ta1 and the third portion or time period Ta2 may beshorter than the first portion or time period Ta1 or the second portionor time period Ta2.

The first portion or time period Ta1 and third portion or time periodTa3 may be equal. Of course, embodiments of the present disclosure arenot limited to the above-described condition. In another embodiment, thefirst portion or time period Ta1 and third portion or time period Ta3may differ from each other.

The driving signal Vd may have a duty ratio DR more than 0.25, but lessthan 1 (0.25<DR<1). That is, the duty ratio DR of the driving signal Vdmay be within a range of more than 0.25, but less than 1. When the dutyratio DR of the driving signal Vd is not more than 0.25, the averagepower of the driving signal Vd to be transmitted may be reduced by ¼. Inthis case, touch performance may be reduced by 6 dB or more.

The duty ratio DR of the driving signal may be the rate of the sum ofthe first portion or time period Ta1 and third portion or time periodTa3 (Ta1+Ta3) within each period T of the driving signal ((Ta1+Ta3)/T),as compared to the second portion or time period Ta2.

Dotted line portions in FIG. 2 illustrate a driving signal VE having twovoltages of different levels. The driving signal VE transits from thefirst voltage level V+p to the third voltage level −Vn every half periodT/2. At the half period time T/2, the driving signal VE may transitionfrom Vp to Vn.

On the other hand, in one or more embodiments of the present disclosure,the driving signal Vd at a first time t1 may transition from a firstvalue Vp. The driving signal Vd at a second time t2 may transition to avalue Vn.

That is, the transition from Vp or to Vn of the driving signal Vdaccording to the illustrated embodiment(s) is less than the transitionfrom Vp to Vn of the driving signal VE.

Thus, in the illustrated embodiment, it is possible to reduce one ormore harmonic components of or in the driving signal Vd because thedriving signal Vd has three or more voltages of different levels withineach period thereof.

FIG. 4 illustrates examples of a driving signal having two voltages ofdifferent levels and a driving signal having three voltages of differentlevels in accordance with one or more embodiments of the presentdisclosure. FIG. 5 illustrates results of a simulation illustrating aharmonic component of the driving signal of FIG. 4 having two voltagesof different levels. FIG. 6 illustrates results of a simulationillustrating a harmonic component of the driving signal according toembodiment(s) of the present disclosure illustrated in FIG. 4.

In FIG. 4, the solid line depicts the driving signal according toembodiment(s) of the present disclosure, and the dotted line depicts thedriving signal that has two voltages of different levels.

Referring to FIGS. 4 to 6, it can be seen that the harmonic component(s)shown in FIG. 5 is less than that of FIG. 6.

In embodiments of the present disclosure, it is possible to provide thesensing unit with enhancements in sensitivity and jitter immunity of inaccordance with the reduction of the harmonic component(s) in thedriving signal.

Driving signals simultaneously applied to two or more of the drivinglines may have the same phase.

For example, the driving signal Vd illustrated in FIG. 2 may besimultaneously applied to two or more of the driving lines at the samephase.

An overlapped or combined signal Vc (FIG. 3) received by the sensingunit 30 may be a signal having three voltages of different levels.

Here, the “overlapped or combined signal Vc” means a signal inaccordance with results of overlap, summation or combination of drivingsignals applied to each sensing line (for example, Yj in FIG. 3) and/orcoupled to sensing nodes corresponding to the driving lines receivingthe driving signals.

FIG. 7 depicts a signal received by the sensing unit via each sensingline when driving signals having the same phase are simultaneouslyapplied to two or more driving lines corresponding to the sensing line,respectively.

Referring to FIG. 7, when driving signals Vd simultaneously applied totwo driving lines, for example, X1 and X2, have the same phase, themagnitude of the signal Vc (FIG. 3) received by the correspondingsensing line Y1 may be double the magnitude of the driving signal Vdapplied to each driving line, for example, X1 or X2, in accordance witha principle of overlap, summation or combination.

On the other hand, voltage variation of the overlapped or combinedsignal Vc received by the sensing unit 30 may be less than a firstvoltage variation. The first voltage variation may be the voltagevariation of a signal received by the sensing unit when a driving signalhaving two voltages of different levels and the same phase issimultaneously applied to two driving lines, for example, X1 and X2,respectively (hereinafter, referred to as a “first case”).

The overlapped or combined signal Vc (FIG. 3) received by the sensingunit 30 may be a signal having three voltages of different levels.Furthermore, the overlapped or combined signal Vc (FIG. 3) received bythe sensing unit 30 may have a fourth voltage level, +2Vp, the secondvoltage level Vss, and a fifth voltage level, −2Vn.

In embodiments of the present disclosure, it is possible to reduce themaximum peak current of the overlapped or combined signal Vc received bythe sensing unit 30, as compared to the first case, and, as a result,the design specification of the sensing unit 30 may be relaxed, ascompared to the first case.

In accordance with an increase in the magnitude of the overlapped orcombined signal Vc (FIG. 9) received by the sensing unit 30, it ispossible to achieve an enhancement in signal to noise ratio of thesensing signal Vs (FIG. 3) received by the sensing unit 30.

The phase of the driving signal applied to at least one of the selecteddriving lines may differ from the phases of the driving signals appliedto the remaining driving lines.

For example, different phases of the driving signal Vd illustrated inFIG. 2 may be simultaneously applied to two or more driving lines.

FIG. 8 illustrates an example in which at least one driving signalsimultaneously applied to driving lines has a phase different from thoseof the remaining driving signals.

Referring to FIG. 8, the driving signal applied to one or more of thedriving lines (for example, an odd number of driving lines X1, X2, andX3, or just X2), may have a phase different from the driving signalsapplied to the remaining driving lines (for example, X1 and X3).

The driving signal applied to at least one of the driving lines may havea phase difference of 180° or a half period from the driving signalsapplied to the remaining driving lines.

For example, the phases of the driving signals applied to the first andthird driving lines X1 and X3 may be identical, while at the same timebeing different from that of the driving signal applied to the seconddriving line X2.

The sensing unit 30 may be electrically connected to the plural sensinglines Y1 to Ym (m being a natural number greater than 1). The sensingunit 30 may sense the capacitance of a node capacitor between a drivingline and a corresponding or overlapping one of the sensing lines.

The driving unit 20 may supply the driving signal Vd to the drivinglines X1 to Xn (n being a natural number greater than 1). The sensingunit 30 may include sensing circuits for sensing signals received by thesensing unit 30 via the sensing lines Y1 to Ym, respectively.

FIG. 3 is an embodiment of the sensing circuit 30-j included in thesensing unit 30 illustrated in FIG. 1.

Although only one sensing circuit 30-j, coupled to the i-th driving lineXi and the j-th sensing line Yj, is illustrated in FIG. 3, the sensingunit 30 may include a plurality of sensing circuits coupled to m sensinglines Y1 to Ym (m being a natural number greater than 1).

Referring to FIG. 3, the sensing circuit 30-j may include an amplifier31 and a capacitor 32.

The amplifier 31 may be a differential amplifier having a first inputterminal 201 (for example, an inverting or negative terminal) coupled tothe sensing line Yj, a second input terminal 202 (for example,non-inverting or positive terminal) connected to the second voltagelevel Vss, and an output terminal 203 for outputting a sensing signalVs. Although an operational amplifier is illustrated as an example ofthe amplifier 31 in FIG. 3, embodiments of the present disclosure arenot limited thereto.

The capacitor 32 is electrically connected between the first inputterminal 201 and the output terminal 203 of the amplifier 31, tonegatively feed back an output from the amplifier 31 to the first inputterminal 201. The capacitor 32 may also determine a gain of the sensingsignal Vs.

The signal Vc received by the sensing circuit 30-j may be a signalobtained by overlapping two or more driving signals simultaneouslydriven through the sensing line Yj.

That is, two or driving signals, which are simultaneously driven, mayoverlap in the sensing line Yj and, as such, an overlapped or combinedsignal, namely, the signal Vc, may be received by the sensing unit 30.

The control unit controls operations of the driving unit 20 and sensingunit 30.

For example, the control unit 40 may generate a driving control signalSx for control of the driving unit 20, and a sensing control signal Syfor control of the sensing unit 30. The control unit 40 controlsoperations of the driving unit 20 and sensing unit 30 in accordance withthe driving control signal Sx and sensing control sign al Sy.

The control unit 40 may sense the signal Vc applied to the sensing lineYj, and may control the sensing unit 30 in accordance with the sensedresults, to output the sensing signal Vs.

As described above, in accordance with the embodiment, it is possible toreduce a harmonic component included in the driving signal whileachieving an enhancement in sensitivity and jitter immunity by applyinga driving signal having three voltages of different levels to two ormore driving lines. This is because separate detection of a desiredsignal and a noise signal can be easily achieved in accordance withreduction of the harmonic component included in the driving signal.

In addition, in accordance with the embodiment, it is possible tocompensate for a delay time due to parasitic capacitance caused by thetouch panel 10 and substrate (for example, a printed circuit board(PCB)). Accordingly, stable operation of the touchscreen device 100 canbe ensured.

Moreover, in accordance with the embodiment, momentary peak current canbe reduced through a reduction in voltage variation of the drivingsignal Vd. Accordingly, it is possible to eliminate glitch of the signalreceived by the sensing unit, and to easily realize the circuit of thesensing unit 30.

FIG. 9 is a method for simultaneously driving two driving lines inaccordance with one or more embodiments.

Referring to FIG. 9, two driving lines selected from among a pluralityof driving lines X1 to Xn (n being a natural number greater than 1; forexample, the driving lines X1 and X2) can be simultaneously driven. Eachof the driving signals for simultaneous driving of the two selecteddriving lines (for example, driving signals Vd1 and Vd2 for the drivinglines X1 and X2) may have voltages of different levels.

In the illustrated embodiment, the overlapped or combined signal Vcreceived by the sensing unit 30 may have three voltages of differentlevels via the sensing line (for example, Y1) through adjustment of thephases and/or adjustment, combination and/or summation of voltage levelsof the driving signals, each having two voltages of different levels.The overlapped or combined signal Vc may be a periodic signal having acertain period T.

Here, the “overlapped or combined signal Vc” generally means a signal inaccordance with results of overlap, combination and/or summation ofdriving signals (for example, Vd1 and Vd2) applied to each sensing line(for example, Y1 in FIG. 3) coupled to sensing nodes (for example, C11and C21 in FIG. 3) corresponding to two driving lines (for example, X1and X2) receiving the driving signals.

The overlapped or combined signal Vc received by the sensing unit 30 maybe a periodic signal.

The period T of the overlapped or combined signal Vc may be divided intofirst to fourth portions or time periods T1 to T4, which are sequential.The signal Vc overlapped or combined for one period T may sequentiallyinclude a first section, portion or time period having a first voltagelevel, a second section, portion or time period having a second voltagelevel, a third section, portion or time period having a third voltagelevel, and a fourth section, portion or time period having the secondvoltage level.

The first voltage level, second voltage level, and third voltage levelare different from each other. The first voltage level may be highest,the third voltage level may be lowest, and the second voltage level maybe between the first and third voltage levels (Va1>Va2>Va3).

For example, the first voltage level may be a positive (+) voltage. Thesecond voltage level may be 0 or a ground potential. The third voltagelevel may be a negative (−) voltage.

For example, the overlapped or combined signal Vc received by thesensing unit 30 may include a first signal portion or time period Va1having the first voltage level, a second signal portion or time periodVa2 having the second voltage level, and a third signal portion or timeperiod Va3 having the third voltage level.

The first signal portion or time period Va1 and third signal portion ortime period Va3 may alternate. The second signal portion or time periodVa2 may be between the first signal portion or time period Va1 and thethird signal portion or time period Va3.

For example, the overlapped or combined signal Vc may be the firstsignal portion or time period Va1 during the first period T1, the secondsignal portion or time period Va2 during the second period T2, the thirdsignal portion or time period Va2 during the third period T3, and thefourth signal Va4 during the fourth period T4. The fourth signal Va4during the fourth period T4 may have the same voltage and/or length asthe second signal portion or time period Va2 during the second periodT2.

The voltage of the driving signal supplied to one of the two drivinglines during the first period T1 may be the first voltage level, and thevoltage of the driving signal supplied to the other driving line duringthe first period T1 may be the second voltage level. Alternatively, thevoltages of the driving signals respectively supplied to the two drivinglines during the first period T1 may be the first voltage level.

For example, the voltages (for example, A1 and B1) of the drivingsignals Vd1 and Vd2 respectively supplied to two driving lines (forexample, X1 and X2) during the first period T1 may be voltages (+, 0) orvoltages (+, +), respectively.

The voltage of the driving signal supplied to one of the two drivinglines during the second period T2 or during the fourth period T4 may bethe first voltage level, and the voltage of the driving signal suppliedto the other driving line during the second period T2 or during thefourth period T4 may be the third voltage level. Alternatively, thevoltages of the driving signals respectively supplied to the two drivinglines during the second period T2 or during the fourth period T4 may bethe second voltage level.

For example, the voltages (for example, A2 and B2) of the drivingsignals Vd1 and Vd2 respectively supplied to two driving lines (forexample, X1 and X2) during the second period T2 may have voltages (0, 0)or voltages (+, −), respectively. On the other hand, the voltages (forexample, A4 and B4) of the driving signals Vd1 and Vd2 respectivelysupplied to two driving lines (for example, X1 and X2) during the fourthperiod T4 may have voltages (0, 0) or voltages (+, −) or (−, +),respectively.

The voltage of the driving signal supplied to one of the two drivinglines during the third period T3 may be the third voltage level, and thevoltage of the driving signal supplied to the other driving line duringthe third period T3 may be the second voltage level. Alternatively, thevoltages of the driving signals respectively supplied to the two drivinglines during the third period T3 may be the third voltage level.

For example, the voltages (for example, A3 and B3) of the drivingsignals Vd1 and Vd2 respectively supplied to two driving lines (forexample, X1 and X2) during the third period T3 may have voltages (−, −)or voltages (−, 0), respectively.

Here, “+” represents the first voltage level, “0” represents the secondvoltage level, and “−” represents the third voltage level.

Although FIG. 9 illustrates an example in which two driving lines aresimultaneously driven, embodiments of the present disclosure are notlimited thereto.

For example, the overlapped or combined signal Vc received by thesensing unit 30 during each of the periods T1 to T4 may have voltages asillustrated in FIG. 9, through adjustment of the phases and/oradjustment, combination and/or summation magnitudes of the drivingsignals respectively supplied to the two or more driving lines. Oneskilled in the art can add or combine one or more additional signalshaving a phase and/or magnitude as shown in any of FIGS. 10A-C, or asmaller magnitude (for example as provided by a conventional voltagedivider), to form an overlapped or combined signal having more than 3voltage levels.

FIGS. 10A to 10C illustrate examples of two driving signals Vd1 and Vd2illustrated in FIG. 9 that overlap or are combined, added or summed toform the overlapped or combined driving signal Vc.

Referring to FIGS. 10A to 10C, each of the first and second drivingsignals Vd1 and Vd2 may have two voltages from among the first voltagelevel +Vp, second voltage level Vss, and third voltage level −Vn.

The overlapped or combined signal Vc received by the sensing unit 30during each of the periods T1 to T4 may have three voltages of differentlevels, Vap, Vss, and Van, in one period T, through adjustment,combination and/or summation of the phases and/or magnitudes of thefirst and second driving signals Vd1 and Vd2.

FIG. 11 illustrates a method for simultaneously driving two drivinglines in accordance with another embodiment.

Referring to FIG. 11, each of the driving signals Vd1 and Vd2 forsimultaneous driving of two selected driving lines (for example, thedriving lines X1 and X2) may have voltages of different levels.

In addition, each driving signal Vd1 and Vd2 for simultaneous driving ofthe two selected driving lines (for example, the driving lines X1 andX2) may be a periodic signal having a certain period. The drivingsignals Vd1 and Vd2 may have the same phase.

The first and second driving signals Vd1 and Vd2 may have the samevoltage in each of the first to fourth periods T1 to T4.

For example, the voltage of each of the first and second driving signalsVd1 and Vd2 in the first period T1 may be the first voltage level +Vp.The voltage of each of the first and second driving signals Vd1 and Vd2in the second period T2 and/or in the fourth period T4 may be the secondvoltage level Vss. The voltage of each of the first and second drivingsignals Vd1 and Vd2 in the third period T3 may be the third voltagelevel −Vn.

In this embodiment, the overlapped or combined signal Vc received by thesensing unit 30 may have three voltages of different levels throughadjustment of the phases and/or adjustment, combination and/or summationof the magnitudes of two driving signals (for example, Vd1 and Vd2).

Since the overlapped or combined signal Vc received by the sensing unit30 has three voltages of different levels, it is possible to reduce aharmonic component of the overlapped or combined signal Vc. As result,the filter specification for signal detection may be relaxed. Inaddition, when the driving signals Vd1 and Vd2 have the same phase, itis possible to reduce influence caused by interference of driving lines(for example, X1 and X2.

Although embodiments of the present disclosure have been described withreference to a number of illustrative embodiments thereof, it should beunderstood that numerous other modifications and embodiments can bedevised by those skilled in the art that will fall within the spirit andscope of the principles of this disclosure. More particularly,variations and modifications are possible in the component parts and/orarrangements of the subject combination and/or arrangement within thescope of the disclosure, the drawings and the appended claims. Inaddition to variations and modifications in the component parts and/orarrangements, alternative uses will also be apparent to those skilled inthe art.

What is claimed is:
 1. A method for driving a touch panel includingdriving lines, sensing lines, and node capacitors between neighboringand/or overlapping driving lines and sensing lines, comprising:selecting two or more of the driving lines; and simultaneously drivingthe selected driving lines with driving signals, wherein each drivingsignal has three or more voltages of different levels.
 2. The methodaccording to claim 1, wherein each driving signal is a periodic signal,and has three voltages of different levels during each period.
 3. Themethod according to claim 2, wherein: each driving signal comprises: afirst signal portion or time period having a first voltage level, asecond signal portion or time period having a second voltage level, anda third signal portion or time period having a third voltage level; andthe first voltage level, the second voltage level, and the third voltagelevel are different from each other.
 4. The method according to claim 3,wherein the first voltage level is higher than the second voltage level,and the second voltage level is higher than the third voltage level. 5.The method according to claim 4, wherein the first voltage level is apositive (+) voltage, the second voltage level is 0 or a groundpotential, and the third voltage level is a negative (−) voltage.
 6. Themethod according to claim 4, wherein the first signal portion or timeperiod and the third signal portion or time period alternate, and thesecond signal portion or time period is between the first signal portionor time period and the third signal portion or time period.
 7. Themethod according to claim 3, wherein: each driving signal has a dutyratio within a range of more than 0.25, but less than 1; and the dutyratio of each driving signal is a ratio or percentage of a sum of alength of the first period and a length of the third signal portion ortime period in each period of the driving signal.
 8. The methodaccording to claim 1, wherein the driving signals have a same phase. 9.The method according to claim 1, wherein the driving signal applied toat least one of the selected driving lines has a phase different fromthe driving signals applied to remaining driving lines.
 10. The methodaccording to claim 3, wherein the first signal portion or time periodand the third signal portion or time period of each driving signal haveequal lengths.
 11. The method according to claim 6, wherein the secondsignal portion or time period is before the first signal portion or timeperiod and/or after the third signal portion or time period.
 12. Amethod for driving a touch panel including driving lines, sensing lines,and node capacitors between neighboring and/or overlapping driving linesand sensing lines, comprising: selecting two or more of the drivinglines; and simultaneously driving the selected driving lines withdriving signals, wherein each driving signal is a periodic signal havinga period comprising a first portion or time period in which the drivingsignal has a first voltage level, a second portion or time period inwhich the driving signal has a second voltage level lower than the firstvoltage level, and a third period in which the driving signal has aportion or time third voltage level lower than the second voltage level.13. The method according to claim 12, wherein: each driving signal has aduty ratio within a range of more than 0.25, but less than 1; and theduty ratio of each driving signal is a ratio or percentage of a sum of alength of the first portion or time period and a length of the thirdportion or time period in each period of the driving signal.
 14. Themethod according to claim 12, wherein at least a portion of the secondportion or time period is between the first portion or time period andthe third portion or time period.
 15. The method according to claim 14,wherein a length of the first portion or time period and a length of thethird portion or time period are equal.
 16. The method according toclaim 14, wherein the portion of the second portion or time periodbetween the first portion or time period and the third portion or timeperiod is shorter than the first portion or time period or the thirdportion or time period.
 17. The method according to claim 12, whereinthe driving signals have a same phase.
 18. The method according to claim12, wherein the driving signal applied to at least one of the selecteddriving lines has a phase different from the driving signals applied toremaining driving lines.
 19. A method for driving a touch panelincluding driving lines, sensing lines, and node capacitors betweenneighboring and/or overlapping driving lines and sensing lines,comprising: selecting two or more of the driving lines; simultaneouslydriving the selected driving lines with driving signals having twovoltages of different levels; and receiving an overlapped or combinedsignal of the simultaneously-driven driving signals, wherein theoverlapped or combined signal is a periodic signal having three or morevoltages of different levels.
 20. The method according to claim 19,wherein the overlapped or combined signal has a period sequentiallycomprising a first portion or time period in which the overlapped orcombined signal has a first voltage level, a second portion or timeperiod in which the overlapped or combined signal has a second voltagelevel lower than the first voltage level, a third portion or time periodin which the overlapped or combined signal has a third voltage levellower than the second voltage level, and a fourth portion or time periodin which the overlapped or combined signal has the second voltage level.